[Illustration: The Fowey Rocks Lighthouse, Florida.] Fowey Reef lies five miles from the low coral island of Soldier Key. Northern storms, sweeping down the Atlantic, brush in wild breakers over the reef and out upon the little key, often burying it entirely under a torrent of water. Even in calm weather the sea is rarely quiet enough to make it safe for a vessel of any size to approach the reef. The builders erected a stout elevated wharf and store-house on the key, and brought their men and tools to await the opportunity to dart out when the sea was at rest and begin the work of marking the reef. Before shipment, the lighthouse, which was built in the North, was set up, complete from foundation to pinnacle, and thoroughly tested. At length the workmen were able to remain on the reef long enough to build a strong working platform twelve feet above the surface of the water, and set on iron-shod mangrove piles. Having established this base of operations in the enemy's domain, a heavy iron disk was lowered to the reef, and the first pile was driven through the hole at its centre. Elaborate tests were made after each blow of the sledge, and the slightest deviation from the vertical was promptly rectified with block and tackle. In two months' time nine piles were driven ten feet into the coral rock, the workmen toiling long hours under a blistering sun. When the time came to erect the superstructure, the sea suddenly awakened and storm followed storm, so that for weeks together no one dared venture out to the reef. The men rusted and grumbled on the narrow docks of the key, and work was finally suspended for an entire winter. At the very first attempt to make a landing in the spring, a tornado drove the vessels far out of their course. But a crew was finally placed on the working platform, with enough food to last them several weeks, and there they stayed, suspended between the sea and the sky, until the structure was complete. This lighthouse cost $175,000. The famous Bug Light of Boston and Thimble Light of Hampton Roads, Va., are both good examples of the iron-pile lighthouse. Now we come to a consideration of iron cylinder lighthouses, which are even more wonderful, perhaps, than the screw-piles, and in constructing them the sea-builder touches the pinnacle of his art.